1. Technical Field
The present invention relates to a light-emitting device which uses a light-emitting material such as an organic electroluminescent (EL) material.
2. Related Art
A light-emitting device having light-emitting elements which use an organic EL material and are arranged on a display region of a substrate is hitherto suggested. The light-emitting element includes a first electrode (anode), a second electrode (cathode), and a light-emitting functional layer which emits light according to current between the two electrodes. A potential corresponding to the luminance for light emission is supplied to the first electrode, and a lower power supply potential is supplied to the second electrode. In JP-A-2001-109395 and JP-A-2013-54863, a light-emitting device in which a power supply wiring which is connected to the second electrode of the light-emitting element and supplies the power supply potential is formed in the periphery of the display region in the plan view is disclosed.
In the technique of JP-A-2001-109395, the power supply wiring and the second electrode are connected to each other via a relay conductor. Specifically, the power supply wiring is covered with an insulating layer (wiring side insulating layer), and the relay conductor is formed on the surface of the wiring side insulating layer. The power supply wiring and the relay conductor are connected to each other via a conduction hole of the wiring side insulating layer. In addition, the relay conductor is covered with an insulating layer (electrode side insulating layer), and the second electrode is formed on the surface of the electrode side insulating layer. The second electrode and the relay conductor are connected to each other via a conduction hole of the electrode side insulating layer. In the technique of JP-A-2001-109395, the conduction hole of the wiring side insulating layer and the conduction hole of the electrode side insulating layer overlap each other in the plan view. Therefore, there is a problem in that there is a height difference of a height corresponding to the sum of the film thicknesses of the wiring side insulating layer and the electrode side insulating layer, between the surface of a region of the second electrode positioned outside the conduction hole in the plan view and the surface of a region thereof that penetrates into the conduction hole.
In the technique of JP-A-2013-54863, the second electrode is formed on the surface of the light-emitting functional layer in the display region and is electrically connected to a power supply wiring (peripheral wiring) via a conduction hole formed in an insulating layer in the periphery of the display region. However, the peripheral edge of the light-emitting functional layer overlaps the inside of the conduction hole (that is, a partial region of the conduction hole is covered with the light-emitting functional layer) used for conduction between the second electrode and the power supply wiring (peripheral wiring), and thus the second electrode and the peripheral wiring may not come into contact with each other anywhere in the entire region of the conduction hole. Therefore, compared to a configuration in which the second electrode and the peripheral wiring come into contact with each other in the entire region of the conduction hole, an area where the second electrode and the peripheral wiring come into contact with each other in the conduction hole is reduced. Accordingly, there is a problem in that the connection between the second electrode and the peripheral wiring becomes insufficient.